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BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20250923T090000
DTEND;TZID=Europe/Berlin:20250926T170000
DTSTAMP:20250923T094025Z
CREATED:20250228T102157Z
LAST-MODIFIED:20250923T094025Z
UID:7677-1758618000-1758906000@alop.uni-trier.de
SUMMARY:International Workshop on Algorithmic Optimization
DESCRIPTION:As the research training group Algorithmic Optimization (ALOP) at Trier University enters its ninth and final year\, we are excited to host our last international workshop on algorithmic optimization. After seven successful international workshops and eight autumn schools\, this event marks a special opportunity to bring together researchers from across the field and to offer perspectives on its future evolution. \nThe workshop will feature a dynamic program\, including invited plenary talks\, contributed talks\, an engaging session with elevator pitches\, and a lively poster session. Covering the full spectrum of algorithmic optimization\, topics will range from mixed-integer programming to optimization with differential equations\, from applications in the energy sector to advancements in machine learning and data science\, as well as from foundational theory to cutting-edge algorithmic developments. \nConfirmed Invited Speakers: \nCarina Costa (State University of Maringá) \nMatthias Heinkenschloss (Rice University) \nMichael Hintermüller (WIAS Berlin) \nMartine Labbé (Université Libre de Bruxelles) \nMarina Leal (Univeritas Miguel Hernández) \nMarianna de Santis (Universitá degli Studi di Firenze) \nJohannes Thürauf (University of Technology Nuremberg) \nKathrin Welker (Helmut Schmidt University) \nOrganizers: \nMartin Schmidt (Trier University) \nVolker Schulz (Trier University) \nSchedule\, Location and Travel Information:  \n \nSchedule will be uploaded later. \nThe workshop will take place in Building E located on Campus I at Trier University. For travel tips on how to get to Trier\, please check here. Instructions on how to find Campus I are located here.  \nProgram: \nThe program and book of abstracts can be found here.
URL:https://alop.uni-trier.de/event/international-workshop-on-algorithmic-optimization/
LOCATION:Trier University\, E Building\, Universitätsring 15\, Trier\, Germany
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20250120T160000
DTEND;TZID=Europe/Berlin:20250120T170000
DTSTAMP:20250106T121301Z
CREATED:20250106T121301Z
LAST-MODIFIED:20250106T121301Z
UID:7671-1737388800-1737392400@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Sonja Steffensen
DESCRIPTION:On Monday\, January 20\, 2025 at 16:00 c.t. Dr. Sonja Steffensen\, RWTH Aachen\, will speak at the ALOP Colloquium about her recent work. \n  \nRelaxation Approaches for Nonlinear Sparse Optimization Problems \nAbstract: \nIn many applications\, sparse solutions are favoured over non-sparse solutions with comparable objective value\, as for example in statistical and deep learning applications. One approach to induce sparsity relies on the l_0 norm as an additional term in the objective. Often this semicontinuous function is approximated using the continuous and convex l_1-norm as a surrogate function instead. However\, this can lead to suboptimal results with respect to the sparsity properties of the solution. \nIn this talk\, we will present an alternative exact reformulation (with respect to the l_0 norm)  using non-smooth nonlinear functions to formulate the minimization of the number of non-zero entries. The resulting problem is similar (but not equivalent) to the class of mathematical programs with complementarity constraints (MPCC). As for MPCCs relaxing the problem to a standard nonlinear program we can then apply a general nonlinear solver. In our talk we will discuss and relate the relations between the different reformulations in particular with respect to the original problem. Furthermore\, we accompany the theoretical results by some numerical tests using randomly generated data sets. \n  \nPlease join us at 16:00 c.t. in HS 9.
URL:https://alop.uni-trier.de/event/alop-colloquium-with-sonja-steffensen/
LOCATION:Trier University\, E Building\, Universitätsring 15\, Trier\, Germany
CATEGORIES:Colloquium
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20241216T160000
DTEND;TZID=Europe/Berlin:20241216T170000
DTSTAMP:20241112T115510Z
CREATED:20241112T115510Z
LAST-MODIFIED:20241112T115510Z
UID:7632-1734364800-1734368400@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Christina Schenk
DESCRIPTION:On Monday\, December 16\, 2024 at 16:00 c.t. Dr. Christina Schenk\, IMDEA Materials Insitute\, Getafe (Madrid)\, will speak at the ALOP Colloquium about her recent work. \n  \nMixed-dimensional Linked Models and Reinforcement Learning-Based Control of Reaction-Diffusion Problems \nAbstract: \nIn Mathematical modeling is a powerful tool for tackling complex challenges across various fields. For instance\, during the SARS-CoV-2 pandemic\, modeling spatial dynamics and high-diffusion pathways\, such as airways and highways\, proved essential for effective decision-making in managing the crisis. \nIn this talk\, we present two approaches to enhance modeling and decision-making. We start with linking models of different dimensionalities to represent a single physical phenomenon\, specifically coupling two diffusive models—one over a continuum and another over a curve—resulting in a mixed-dimensional problem. We establish the unconditional stability and convergence of both continuous and discrete linked models using mixed finite elements. Supported by numerical examples\, we demonstrate the benefits of combining these models and show how our methods can infer solutions from incomplete data. \nBuilding on these results\, we explore the application of reinforcement learning (RL) to automatic control problems in thermal and disease transport. We adapt a stochastic policy gradient algorithm and propose novel reward functions to guide the RL agent in interacting with a reaction-diffusion model. Our approach successfully implements control strategies despite necessary model simplifications\, showcasing the potential of RL to solve complex control problems. \nBy combining theoretical and numerical insights from mixed-dimensional modeling and machine learning\, this talk highlights new results for advancing diffusive modeling and data-driven control strategies\, opening new avenues for research in data science and control applications. \n  \nThis is joint work with Aditya Vasudevan\, David Portillo (UPM)\, Ignacio Romero\, and Maciej Haranczyk. \n  \nPlease join us at 16:00 c.t. in HS 9.
URL:https://alop.uni-trier.de/event/alop-colloquium-with-christina-schenk/
LOCATION:Trier University\, E Building\, Universitätsring 15\, Trier\, Germany
CATEGORIES:Colloquium
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20241009T080000
DTEND;TZID=Europe/Berlin:20241011T160000
DTSTAMP:20240920T114250Z
CREATED:20240404T072758Z
LAST-MODIFIED:20240920T114250Z
UID:7393-1728460800-1728662400@alop.uni-trier.de
SUMMARY:Autumn School on Constrained Optimization and Machine Learning
DESCRIPTION:The Research Training Group on Algorithmic Optimization proudly announces its eighth Autumn School from October 9 – 11\, 2024. \nThis year’s focus will be on Constrained Optimization and Machine Learning \nIn today’s rapidly evolving technological landscape\, the intersection of constrained optimization and machine learning is gaining immense significance. As we tackle intricate real-world challenges\, the synergy between these two domains gets more and more important. While unconstrained optimization methods have predominantly been employed in machine learning so far\, constraints are becoming prevalent in a wide array of applications. This school offers a unique opportunity to deepen comprehension and delve into the latest advancements at the interface of the two fields. Thus\, participants will acquire invaluable skills to confront the challenges of tomorrow. \n  \nConfirmed Speakers: \nEmilio Carrizosa (University of Sevilla) – Mathematical Modeling for Counterfactual Explanations and Inverse Optimization \nTim Hoheisel (McGill University) – Regularized Least-Squares: Stability Properties and the Maximum Entropy of the Mean Method \nAndrea Lodi (Cornell University) – Machine-Learning-Augmented Mixed-Integer Programming \n  \nOrganizers: \nJan Pablo Burgard (Trier University) \nMartin Schmidt (Trier University) \nVolker Schulz (Trier University) \n  \nSchedule\, Location and Travel Information:  \n \nSchedule can be downloaded here. \nThe workshop will take place in Building E located on Campus I at Trier University. \nFor travel tips on how to get to Trier\, please check  here;\nInstructions on how to find Campus I are located here.  \n  \nRegistration information (registration is closed) \nThe registration fee of 60 € includes a welcome reception\, the conference dinner\, refreshments\, and extra-curricular activities. Detailed payment information will be communicated upon registration.  \n  \nTravel Stipend (application is closed)
URL:https://alop.uni-trier.de/event/autumn-school-on-constrained-optimization-and-machine-learning/
LOCATION:Trier University\, E Building\, Universitätsring 15\, Trier\, Germany
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20240715T170000
DTEND;TZID=Europe/Berlin:20240715T180000
DTSTAMP:20240529T075328Z
CREATED:20240529T075328Z
LAST-MODIFIED:20240529T075328Z
UID:7517-1721062800-1721066400@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Fabio Furini
DESCRIPTION:On Monday\, July 15\, 2024 at 16:00 c.t. Prof. Dr. Fabio Furini\, Sapienza University of Rome\, will speak at the ALOP Colloquium about his recent work. \n  \nSubmodular maximization of concave utility functions composed with a set-union operator with applications to maximal covering location problems \nAbstract: \nWe study a family of discrete optimization problems asking for the maximization of the expected value of a concave\, strictly increasing\, and differentiable function composed with a set-union operator. The expected value is computed with respect to a set of coefficients taking values from a discrete set of scenarios. The function models the utility function of the decision maker\, while the set-union operator models a covering relationship between two ground sets\, a set of items and a set of metaitems. This problem generalizes the problem introduced by Ahmed S\, Atamtürk A (Mathematical programming 128(1-2):149–169\, 2011)\, and it can be modeled as a mixed integer nonlinear program involving binary decision variables associated with the items and metaitems. Its goal is to find a subset of metaitems that maximizes the total utility corresponding to the items it covers. It has applications to\, among others\, maximal covering location\, and influence maximization problems. In the paper\, we propose a double-hypograph decomposition that allows for projecting out the variables associated with the items by separately exploiting the structural properties of the utility function and of the set-union operator. Thanks to it\, the utility function is linearized via an exact outer-approximation technique\, whereas the set-union operator is linearized in two ways: either (i) via a reformulation based on submodular cuts\, or (ii) via a Benders decomposition. We analyze from a theoretical perspective the strength of the inequalities of the resulting reformulations\, and embed them into two branch-and-cut algorithms. We also show how to extend our reformulations to the case where the utility function is not necessarily increasing. We then experimentally compare our algorithms inter se\, to a standard reformulation based on submodular cuts\, to a state-of-the-art global-optimization solver\, and to the greedy algorithm for the maximization of a submodular function. The results reveal that\, on our testbed\, the method based on combining an outer approximation with Benders cuts significantly outperforms the other ones. \n  \nPlease join us at 16:00 c.t. in HS 9.
URL:https://alop.uni-trier.de/event/alop-colloquium-with-fabio-furini/
LOCATION:Trier University\, E Building\, Universitätsring 15\, Trier\, Germany
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20240513T080000
DTEND;TZID=Europe/Berlin:20240514T160000
DTSTAMP:20240528T133025Z
CREATED:20230627T130802Z
LAST-MODIFIED:20240528T133025Z
UID:7186-1715587200-1715702400@alop.uni-trier.de
SUMMARY:Variational Analysis and Applications for Modeling of Energy Exchange - VAME 2024
DESCRIPTION:We proudly announce hosting the third International Workshop on “Variational Analysis and Applications for Modeling of Energy Exchange” from May 13 to 14\, 2024 in Trier. \nThe aim of the workshop is to bring together specialists in the modeling of energy exchanges\, both from the point of view of Mathematics and Economics. In addition\, the workshop strives to stimulate the exchange of ideas among researchers and practitioners that develop or apply energy market models and approaches for policy identification and assessment. In an “informal context”\, the intent is to generate fruitful scientific exchanges on the following topics:  \n\nNonlinear optimization\,\nStochastic programming and robust optimization\,\nBilevel programming\, MPEC\, EPEC\,\nGeneralized Nash equilibrium problems (GNEPs)\,\nCapacity expansion models in renewable dominated power system\,\nDecarbonization and integration of renewable energy sources in power systems\,\nImpact of the development of electric vehicles\,\nElectricity market design\,\nRisk management in electricity markets.\n\nInvited Speakers: \n\nLuce Brotcorne\nJohn Cotrina (slides)\nMel Devine (slides)\nSteve Gabriel (slides)\nRené Henrion\nJalal Kazempour (slides)\nFrauke Liers (slides)\nGiorgia Oggioni\nSalvador Pineda (slides)\nRossana Riccardi\nClaudia Sagastizábal\nSimone Sagratella (slides)\nAfzal Siddiqui (slides)\nRamteen Sioshansi (slides)\nOliver Stein (slides)\nAnton Svensson\nJohannes Thürauf (slides)\nWim Van Ackooij\n\nScientific Committee: \n\nMiguel Anjos\nDidier Aussel\nMartine Labbé\nLorenzo Lampariello\nGiorgia Oggioni\nRossana Riccardi\nDavid Salas\nMartin Schmidt\nAlexandra Schwartz\nGregor Zöttl\n\nOrganizing Committee: \n\nLaura Sokolowski\nMartin Schmidt\n\nSchedule and location \nSchedule can be downloaded here. \nThe workshop will take place at the Bischöflisches Priesterseminar Trier. \nRegistration information (registration is closed)
URL:https://alop.uni-trier.de/event/variational-analysis-and-applications-for-modelling-of-energy-exchange-vame-2024/
LOCATION:Bischöfliches Priesterseminar Trier\, Jesuitenstraße 13\, Trier\, 54290
CATEGORIES:Workshop
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20240506T160000
DTEND;TZID=Europe/Berlin:20240506T170000
DTSTAMP:20240418T125616Z
CREATED:20240418T123625Z
LAST-MODIFIED:20240418T125616Z
UID:7414-1715011200-1715014800@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Laura Vargas Koch
DESCRIPTION:On Monday\, May 6\, 2024 at 16:00 c.t. Prof. Dr. Laura Vargas Koch\, University of Bonn\, will speak at the ALOP Colloquium about her recent work. \n  \nMathematics in Traffic Modeling: Nash Flows over Time \nAbstract: \nIn traffic planning\, traffic simulations are widely used. However\, effective practical traffic simulations require good mathematical models as a foundation\, and one such model is Nash flows over time. Traffic is not a centrally controlled system. Instead\, each participant in traffic decides individually which route is best for them. When all participants do this\, so-called equilibrium states emerge. In our research\, we focus on these equilibria and their properties. Unlike static\, classical models\, the unique aspect of Nash flows over time is that temporal changes can be depicted. This means that a flow\, which models traffic\, moves through the network over time\, and the situation in the network can dynamically change. In this presentation\, we will learn about the model of Nash flows over time\, understand its close connection to the traffic simulation software MATSim and see what properties of the equilibria have already been understood\, and what questions are still open. \n  \nPlease join us at 16:00 c.t. in HS 9. \n 
URL:https://alop.uni-trier.de/event/alop-colloquium-with-laura-vargas-koch/
LOCATION:Trier University\, E Building\, Universitätsring 15\, Trier\, Germany
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20240226T160000
DTEND;TZID=Europe/Berlin:20240226T170000
DTSTAMP:20240118T072334Z
CREATED:20231019T094016Z
LAST-MODIFIED:20240118T072334Z
UID:7307-1708963200-1708966800@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Boris Detienne
DESCRIPTION:On Monday\, February 26\, 2024 at 16:00 c.t. Prof. Boris Detienne\, University of Bordeaux\, will speak at the ALOP Colloquium about his recent work. \n  \nThe Benders-by-batch algorithm to solve two-stage stochastic linear programs \nAbstract: \nIn this talk\, we will introduce a new exact algorithm to solve two-stage stochastic linear programs. Based on the multicut Benders reformulation of such problems\, with one subproblem for each scenario\, this method relies on a partition of the subproblems into batches. The key idea is to solve at most iterations only a small proportion of the subproblems by detecting as soon as possible that a first-stage candidate solution cannot be proven optimal. We also propose a general framework to stabilize our algorithm\, and show its finite convergence and exact behavior. We report an extensive computational study on large-scale instances of stochastic optimization literature that shows the efficiency of the proposed algorithm compared to nine alternative algorithms from the literature. We also obtain significant additional computational time savings using the primal stabilization schemes \n  \nPlease join us at 16:00 c.t. in HS 9. \n 
URL:https://alop.uni-trier.de/event/alop-colloquium-with-boris-detienne/
LOCATION:Trier University\, E Building\, Universitätsring 15\, Trier\, Germany
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20240212T160000
DTEND;TZID=Europe/Berlin:20240212T170000
DTSTAMP:20231221T143522Z
CREATED:20231221T094533Z
LAST-MODIFIED:20231221T143522Z
UID:7334-1707753600-1707757200@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Dorothee Henke
DESCRIPTION:On Monday\, February 12\, 2024 at 16:00 c.t. Dorothee Henke\, University of Passau\, will speak at the ALOP Colloquium about her recent work: \n  \nOn the Complexity of the Bilevel Shortest Path Problem \nAbstract: \nWe introduce a new bilevel version of the classical shortest path problem and completely characterize its computational complexity with respect to several problem variants. In our problem\, the leader and the follower each control a subset of the edges of a graph and together aim at building a path between two given vertices\, while each of the two players minimizes the length of the resulting path according to their own edge lengths. We investigate both directed and undirected graphs\, as well as the special case of acyclic directed graphs. Moreover\, we distinguish two versions of the follower’s problem: Either he has to complete the edge set selected by the leader such that the joint solution is exactly a path\, without any additional edges\, or he is allowed to include only a subset of the leader’s selection into the final path. In general\, the bilevel problem turns out to be much harder in the former case: We show that the follower’s problem is already NP-hard here and the leader’s problem is even hard for the second level of the polynomial hierarchy\, while both problems are one level easier in the latter case. Interestingly\, for acyclic directed graphs\, this difference turns around\, as we give a polynomial-time algorithm for the first version of the bilevel problem\, but it stays NP-hard in the second case. \nThis is joint work with Lasse Wulf. \n  \nPlease join us at 16:00 c.t. in HS 9.
URL:https://alop.uni-trier.de/event/alop-colloquium-with-dorothee-henke/
LOCATION:Trier University\, E Building\, Universitätsring 15\, Trier\, Germany
CATEGORIES:Colloquium
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20231211T160000
DTEND;TZID=Europe/Berlin:20231211T170000
DTSTAMP:20230906T085744Z
CREATED:20230814T123248Z
LAST-MODIFIED:20230906T085744Z
UID:7277-1702310400-1702314000@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Mathias Staudigl
DESCRIPTION:On Monday\, December 11\, 2023 at 16:00 c.t. Prof. Dr. Mathias Staudigl\, University of Mannheim\, will speak at the ALOP Colloquium about his recent work: \n  \nA regularized variance-reduced modified extragradient method for stochastic hierarchical games \nAbstract:\n \nThe theory of learning in games has so far focused mainly on games with simultaneous moves. Recently\, researchers in machine learning have started investigating learning dynamics in games involving hierarchical decision-making. We consider an N-player hierarchical game in which the ith player’s objective comprises of an expectation-valued term\, parametrized by rival decisions\, and a hierarchical term. Such a framework allows for capturing a broad range of stochastic hierarchical optimization problems\, Stackelberg equilibrium problems\, and leader-follower games. We develop an iteratively regularized and smoothed variance-reduced modified extragradient framework for learning hierarchical equilibria in a stochastic setting. We equip our analysis with rate statements\, complexity guarantees\, and almost-sure convergence claims. We then extend these statements to settings where the lower-level problem is solved inexactly and provide the corresponding rate and complexity statements. \n  \nPlease join us at 16:00 c.t. in HS 9.
URL:https://alop.uni-trier.de/event/alop-colloquium-with-mathias-staudigl/
LOCATION:Trier University\, E Building\, Universitätsring 15\, Trier\, Germany
CATEGORIES:Colloquium
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20231207T160000
DTEND;TZID=Europe/Berlin:20231207T170000
DTSTAMP:20231123T093046Z
CREATED:20231123T093046Z
LAST-MODIFIED:20231123T093046Z
UID:7328-1701964800-1701968400@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Falk Hante
DESCRIPTION:On Thursday\, December 7\, 2023 at 16:00 c.t. Prof. Dr. Falk Hante\, will speak at the ALOP Colloquium about his recent work: \n  \nTime-Domain Decomposition for Mixed-Integer Optimal Control Problems \nAbstract:\n \nWe consider mixed-integer optimal control problems\, whose optimality conditions involve global combinatorial optimization aspects for the corresponding Hamiltonian pointwise in time. We propose a time-domain decomposition\, which makes this problem class accessible for mixed-integer programming using parallel-in-time direct discretizations. The approach is based on a decomposition of the optimality system and the interpretation of the resulting subproblems as suitably chosen mixed-integer optimal control problems on subintervals in time. An iterative procedure then ensures continuity of the states at the boundaries of the subintervals via co-state information encoded in virtual controls. We prove convergence of this iterative scheme for discrete-continuous linear-quadratic problems and present numerical results both for linear-quadratic as well as nonlinear problems. \n  \nPlease join us at 16:00 c.t. in HS 9.
URL:https://alop.uni-trier.de/event/alop-colloquium-with-falk-hante/
LOCATION:Trier University\, E Building\, Universitätsring 15\, Trier\, Germany
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20231204T160000
DTEND;TZID=Europe/Berlin:20231204T170000
DTSTAMP:20231024T083813Z
CREATED:20230814T123308Z
LAST-MODIFIED:20231024T083813Z
UID:7275-1701705600-1701709200@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Marc Pfetsch
DESCRIPTION:On Monday\, December 4\, 2023 at 16:00 c.t. Prof. Dr. Marc Pfetsch\, TU Darmstadt\, will speak at the ALOP Colloquium about his recent work: \n  \nCombinatorial Aspects of Physical Networks \nAbstract:\n \nThis talk considers combinatorial properties of physical networks like water\, gas\, heat\, and electrical networks. One common model are potential-based flows\, for which\, in general\, the corresponding flows depend in a nonlinear way on potentials (e.g.\, pressures) and are unique. The talk will discuss two different topics. The first is how the fact that flows in physical networks are acyclic can be used to strengthen mixed-integer optimization formulations and to derive combinatorial models. The second concerns the recovery of the structure of the network\, given only information at the entries and exits. The talk will demonstrate positive and negative results in this direction. \n  \nPlease join us at 16:00 c.t. in HS 9.
URL:https://alop.uni-trier.de/event/alop-colloquium-with-marc-pfetsch/
LOCATION:Trier University\, E Building\, Universitätsring 15\, Trier\, Germany
CATEGORIES:Colloquium
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20231116T160000
DTEND;TZID=Europe/Berlin:20231116T170000
DTSTAMP:20231113T141958Z
CREATED:20231024T091139Z
LAST-MODIFIED:20231113T141958Z
UID:7310-1700150400-1700154000@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Daniel Walter
DESCRIPTION:On Thursday\, November 16\, 2023 at 16:00 c.t. Prof. Dr. Daniel Walter\, HU Berlin\, will speak at the ALOP Colloquium about his recent work. \nIf you would like to participate via Zoom\, please click here. \n  \nEfficient minimization in spaces of measures: Numerical methods and applications \nAbstract: \nMinimization problems in spaces of (vector) measures naturally emerge in a variety of challenging settings including e.g. inverse problems in acoustics and seismology\, micoscropy\, optimal sensor placement as well as the training of shallow neural networks. \nIn this talk\, we discuss several of these applications\, both from a theoretical and numerical perspective\, highlighting the difficulties posed by the (typical) nonsmoothness of the arising optimization problems as well as the lack of “nice” topological properties in the space of (vector) measures. Different practical solution ansatzes are discussed with a particular focus on generalized conditional gradient methods. \nFinally\, we further underline the practical relevance of “sparse” minimization problems by showing that a huge class of nonsmooth problems can be equivalently rewritten as an optimization problem over  measures on a compact metric space using arguments from convex representation theory. From a practical perspective\, this unification allows the derivation and analysis of an efficient general purpose solution algorithm by “lifting” arguments from the vector measure setting. \n  \nPlease join us at 16:00 c.t. in HS 9.
URL:https://alop.uni-trier.de/event/alop-colloquium-with-daniel-walter/
LOCATION:Trier University\, E Building\, Universitätsring 15\, Trier\, Germany
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230724T080000
DTEND;TZID=Europe/Berlin:20230726T140000
DTSTAMP:20230721T082025Z
CREATED:20230303T115741Z
LAST-MODIFIED:20230721T082025Z
UID:7019-1690185600-1690380000@alop.uni-trier.de
SUMMARY:German SIAM Student Chapters Meet Algorithmic Optimization
DESCRIPTION:The SIAM Student Chapter Trier proudly announces hosting the 6th Symposium of the German SIAM Student Chapters together with the Research Training Group on Algorithmic Optimization (ALOP) in 2023. The meeting is organized as a workshop titled “German SIAM Chapters Meet Algorithmic Optimization.“ This three-day event is scheduled to take place in person at Trier University. \nScope \nThe workshop targets the members of the German SIAM Student Chapters but other interested individuals are also welcome to participate. The goal is to bring together researchers from various fields of mathematical optimization and applied mathematics to exchange ideas from different research groups. In particular\, the aim of the workshop is to strengthen the connection of early career researchers from across Germany as well as to network with experienced invited plenary speakers. \nThe topics shall include but are not limited to \n\nSystem Models (PDE Constrained Optimization\, Model Order Reduction\,…)\nOptimization (Discrete Optimization\, Non-Smooth Optimization\, Shape Optimization\,…)\nStatistics\, Data Analysis\, and Machine Learning\n\nThere will be four plenary talks\, contributed talks by early career researchers\, and a poster session. \nConfirmed speakers: \nRoland Herzog (Heidelberg University) \nDaniel Walter (HU Berlin) \nChristina Brandt (Universität Hamburg) \nLaura Scarabosio (Radboud University Nijmegen) \nOrganizers: \nVolker Schulz (Trier University) \nYasmine Beck (Trier University) \nMaximilian Würschmidt (Trier University) \nProgramm Committee: \nYasmine Beck (Trier University) \nJosie König (University of Potsdam) \nHenrik Wyschka (Universität Hamburg) \nTimo Kreimeier (HU Berlin) \nSchedule\, Location\, and Travel Information:\n \nWorkshop Program - German SIAM Student Chapters meet Algorithmic Optimization\nSchedule can be downloaded here. \nThe workshop will take place in Building E located on Campus I at Trier University. \nFor travel tips on how to get to Trier\, please check  here;\nInstructions on how to find Campus I are located here.  \nYou would like to give a short presentation yourself? Send an e-mail to: sokolowski@uni-trier.de \nHotel Room Reservations: \nWe have reserved a hotel room contingent at the Best Western Hotel Trier City\, Kaiserstraße 29\, 54290 Trier. Please contact them directly to make your reservations under the keyword “ALOP”. \nThe contingent will be available for reservation until June 23\, 2023\, or until all available rooms have been booked. \nRegistration is closed.
URL:https://alop.uni-trier.de/event/german-siam-student-chapters-meet-algorithmic-optimization/
LOCATION:Trier University – E-Building – HS 9\, Universität Trier Gebäude E\, Trier\, Rhineland-Palatinate\, 54296\, Germany
CATEGORIES:Workshop
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230717T160000
DTEND;TZID=Europe/Berlin:20230717T170000
DTSTAMP:20230704T090825Z
CREATED:20230704T090825Z
LAST-MODIFIED:20230704T090825Z
UID:7238-1689609600-1689613200@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Gabriele Dragotto
DESCRIPTION:On Monday\, July 17\, 2023 at 16:00 c.t. Dr. Gabriele Dragotto\, Princeton University\, will speak at the ALOP Colloquium about his recent work: \n  \nLearn-and-Play: Data\, Agents\, and Interactions \nAbstract: \nHow should an energy company determine its optimal production schedule? How should transport authorities design transportation networks? How should graduate students from medical schools be matched with residency training? In all these contexts\, decision-making is rarely an individual task; on the contrary\, it often involves the mutual interaction of several self-interested decision-makers deciding by solving optimization problems. However\, the agents’ self-driven behavior often conflicts with the greater societal goals; in such cases\, external regulators (e.g.\, governments) can intervene in the agents’ interaction via incentives\, laws\, and regulations. This talk provides a method for learning the agents’ preferences from data to design prescriptive interventions that possibly improve social welfare.  \n  \nPlease join us at 16:00 c.t. in HS 10.
URL:https://alop.uni-trier.de/event/alop-colloquium-with-gabriele-dragotto/
LOCATION:Trier University\, E Building\, Universitätsring 15\, Trier\, Germany
CATEGORIES:Colloquium
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230626T160000
DTEND;TZID=Europe/Berlin:20230626T170000
DTSTAMP:20230620T065239Z
CREATED:20230102T140258Z
LAST-MODIFIED:20230620T065239Z
UID:6983-1687795200-1687798800@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Alexander Martin
DESCRIPTION:On Monday\, June 26\, 2023 at 16:00 c.t. Prof. Dr. Alexander Martin\, Fraunhofer IIS; Technische Universität Nürnberg \, will speak at the ALOP Colloquium about his recent work: \n  \nMixed Integer Optimization Problems on Networks with PDE Constraints \nAbstract: \nMotivated by challenging questions in the transformation and control of our energy system we study mixed integer optimization problems on networks with PDE constraints. Control decisions are typically modeled by integer optimization methods\, while the physical behavior of water\, gas and hydrogen is represented in a continuous nonlinear way\, e.g. by partial differential equations (PDEs). \nThe topic of this talk is to discuss mathematical approaches and insights for the efficient coupling of integer and continuous nonlinear optimization in this context. \nWe will also demonstrate the numerical success using examples from gas network optimization within the framework of the SFB/TR 154. \n  \nPlease join us at 16:00 c.t. in HS 10. \n  \n 
URL:https://alop.uni-trier.de/event/alop-colloquium-with-alexander-martin/
LOCATION:Trier University\, E Building\, Universitätsring 15\, Trier\, Germany
CATEGORIES:Colloquium
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230612T160000
DTEND;TZID=Europe/Berlin:20230612T170000
DTSTAMP:20230420T141310Z
CREATED:20230420T141310Z
LAST-MODIFIED:20230420T141310Z
UID:7133-1686585600-1686589200@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Steven Gabriel
DESCRIPTION:On Monday\, June 12\, 2023 at 16:00 c.t. Prof. Steven Gabriel\, University of Maryland\, will speak at the ALOP Colloquium about his recent work: \n  \nBilevel Optimization for Infrastructure Management (energy\, water\, environment\, transportation) \nAbstract: \nIn this talk we present both motivation for and examples of bilevel optimization/mathematical programs with equilibrium constraints (MPECs) as applied to better management of infrastructure.  In this setting\, infrastructure means energy\, water\, transportation\, and the environment.  We focus on a diverse set of application areas\, the need to incentivize users of the related infrastructure networks to participate in an efficiency manner\, and then describe some recent work as applied to the power system in Denmark including theoretical and numerical results and algorithms. \n  \nPlease join us at 16:00 c.t. in HS 10.
URL:https://alop.uni-trier.de/event/alop-colloquium-with-steven-gabriel/
LOCATION:Trier University\, E Building\, Universitätsring 15\, Trier\, Germany
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230515T160000
DTEND;TZID=Europe/Berlin:20230515T170000
DTSTAMP:20230509T105746Z
CREATED:20230102T135859Z
LAST-MODIFIED:20230509T105746Z
UID:6981-1684166400-1684170000@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Marc Steinbach
DESCRIPTION:On Monday\, May 15\, 2023 at 16:45 c.t. Prof. Dr. Marc Steinbach\, Leibniz Universität Hannover\, will speak at the ALOP Colloquium about his recent work: \n  \nNLP Models for Generating Synthetic Vascular Trees \nAbstract: \nWe introduce a new framework for generating synthetic vascular trees based on NLP models for optimizing the local and global tree geometry. A second novelty is a metaheuristic optimization step for the tree topology. \nThe talk discusses these optimization models and compares the new algorithm to the standard CCO approach for generating vascular trees. Moreover\, it compares the influence of different model variants on trees with 14 branching levels and roughly two million nodes. \nThe validation against a corrosion cast of a human liver shows that the trees generated by our new framework match the physiological data better than those generated by the standard CCO approach. \n  \nPlease join us at 16:45 c.t. in HS 10. \n 
URL:https://alop.uni-trier.de/event/alop-colloquium-with-marc-steinbach/
LOCATION:Trier University\, E Building\, Universitätsring 15\, Trier\, Germany
CATEGORIES:Colloquium
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230424T160000
DTEND;TZID=Europe/Berlin:20230424T170000
DTSTAMP:20230329T140042Z
CREATED:20230102T135641Z
LAST-MODIFIED:20230329T140042Z
UID:6979-1682352000-1682355600@alop.uni-trier.de
SUMMARY:ALOP Colloquium with René Henrion
DESCRIPTION:On Monday\, April 24\, 2023 at 16:00 c.t. Dr. René Henrion\, WIAS Berlin\, will speak at the ALOP Colloquium about his recent work: \n  \nAbstract: \nChance constraints are widely used in stochastic programming when inequality constraints in an optimization problem are affected by some random parameter. A chance constraint then defines a decision to be feasible whenever the constraint is satisfied at some specified probability. \nOriginally developed in the framework of operations research\, chance constraints attract increasing attention also in risk averse optimal control problems. \nThe talk addresses various aspects of chance constraints related with applications\, numerics and optimality conditions in PDE-constrained optimization. \n  \nPlease join us at 16:00 c.t. in HS 10.
URL:https://alop.uni-trier.de/event/alop-colloquium-with-rene-henrion/
LOCATION:Trier University\, E Building\, Universitätsring 15\, Trier\, Germany
CATEGORIES:Colloquium
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230213T160000
DTEND;TZID=Europe/Berlin:20230213T170000
DTSTAMP:20230202T125328Z
CREATED:20221129T151056Z
LAST-MODIFIED:20230202T125328Z
UID:6897-1676304000-1676307600@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Marc Goerigk
DESCRIPTION:On Monday\, February 13\, 2023 at 16:00 c.t. Prof. Dr. Marc Goerigk\, University of Siegen\, will speak at the ALOP Colloquium about his recent work: \n  \nModels for Interpretable Optimization \nAbstract: \nWhile explainability and interpretability has become a major research area in machine learning over the past years\, in operations research and mathematical programming the comprehensibility of solutions is hardly every scrutinized. Likely due to the existence of explicitly stated models and well defined solution processes\, experts have high confidence in the correctness and usefulness of found solutions. However\, even understanding a mathematical model can quickly become a challenging task\, especially for people not familiar with modeling techniques. Users with less mathematical and computer background\, e.g. the planner using the optimization software and the workers in charge of implementing the result\, may consider the solver a black box. We present and experimentally validate a modeling framework that inherently provides an interpretable decision rule\, trying to clarify the causal effect of occurring scenario and selected solution. By restricting the number of eligible solutions and providing an interpretable rule\, e.g. in form of a decision tree\, we shift the focus towards comprehensibility and transparency. Our experiments indicate that the costs of interpretability can be small\, i.e.\, only a small percentage of nominal performance needs to be sacrificed. \n  \nPlease join us at 16:00 c.t. in HS 9. \n 
URL:https://alop.uni-trier.de/event/alop-colloquium-with-marc-goerigk/
LOCATION:Trier University\, E Building\, Universitätsring 15\, Trier\, Germany
CATEGORIES:Colloquium
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230206T164500
DTEND;TZID=Europe/Berlin:20230206T174500
DTSTAMP:20230126T125829Z
CREATED:20221130T082641Z
LAST-MODIFIED:20230126T125829Z
UID:6913-1675701900-1675705500@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Hanno Gottschalk
DESCRIPTION:On Monday\, February 6 2023 at 16:00 c.t. Prof. Dr. Hanno Gottschalk\, University of Wuppertal\, will speak at the ALOP Colloquium about his recent work: \n  \nTheory and Applications of Generative Adversarial Learning \nAbstract: \nGenerative learning is the machine learning task of learning to synthesize new examples that assimilate a given distribution. Since the introduction of generative adversarial networks in the year 2014\, generative learning underwent a rapid development and reached a considerable technological level. \nIn this talk\, generative adversarial learning is studied from a mathematical point of view. However\, we also give applications on domain transfer and sampling from the invariant measure of ergodic processes. \n  \nPlease join us at 16:45 c.t. in HS 10.
URL:https://alop.uni-trier.de/event/alop-colloquium-with-prof-dr-hanno-gottschalk-2/
LOCATION:Trier University\, E Building\, Universitätsring 15\, Trier\, Germany
CATEGORIES:Colloquium
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230130T160000
DTEND;TZID=Europe/Berlin:20230130T170000
DTSTAMP:20230124T080128Z
CREATED:20230116T141030Z
LAST-MODIFIED:20230124T080128Z
UID:6991-1675094400-1675098000@alop.uni-trier.de
SUMMARY:CANCELED - ALOP Colloquium with Mark Vogelsberger
DESCRIPTION:Unfortunately\, the talk has to be rescheduled. \nAs soon as there is a new date\, we will announce it here.
URL:https://alop.uni-trier.de/event/alop-colloquium-with-mark-vogelsberger/
CATEGORIES:Colloquium
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20230123T160000
DTEND;TZID=Europe/Berlin:20230123T170000
DTSTAMP:20221216T110910Z
CREATED:20221130T084745Z
LAST-MODIFIED:20221216T110910Z
UID:6893-1674489600-1674493200@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Jannis Kurtz
DESCRIPTION:On Monday\, January 23\, 2023 at 16:00 c.t. Dr. Jannis Kurtz\, University of Amsterdam\, will speak at the ALOP Colloquium about his recent work: \n  \nDeriving Robust Counterfactual Explanations for Machine Learning Models via Two-Stage Robust Optimization \nAbstract: \nNowadays machine learning models are often used to make decisions based on personal data which significantly affect individuals\, e.g. the decision of granting a loan to a person or not. However many machine learning models behave like black-boxes and can incorporate biases contained in the data into their decision which is why in 2016 the European Union enacted the “right to explanation”.   \nCounterfactual explanations (CE) play an important role in providing such explanations and hence improving explainability. The idea is to find the smallest changes which have to be made to a data point such that the model would have changed its decision. Unfortunately most of the common methods can only provide one CE which can be unrealistic to reach for the user. \nIn this work we present a model to calculate robust CEs\, i.e. CEs where after changing each attribute in a certain range the perturbed data point still remains a CE. Hence our method provides a whole set of CEs and the user can choose the one which is most reasonable. We use algorithmic ideas from two-stage robust optimization to calculate robust CEs for the most popular ML methods including logistic regression\, decision trees and neural networks. We show that our method is able to calculate CEs efficiently for common data sets. \n  \nPlease join us at 16:00 c.t. in HS 9. \n 
URL:https://alop.uni-trier.de/event/alop-colloquium-with-jannis-kurtz/
LOCATION:Trier University E Building\, Universitätsring 15\, Trier\, 54296\, Germany
CATEGORIES:Colloquium
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20221128T160000
DTEND;TZID=Europe/Berlin:20221128T170000
DTSTAMP:20221216T110700Z
CREATED:20221025T102708Z
LAST-MODIFIED:20221216T110700Z
UID:6801-1669651200-1669654800@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Martina Cerulli
DESCRIPTION:On Monday\, November 28 2022 at 16:00 c.t. Martina Cerulli\, ESSEC Business School of Paris\, will speak at the ALOP Colloquium about her recent work: \n  \nOn the dualization of the inner problems of Semi-Infinite programs \nAbstract: \nIn this talk\, we will discuss a solution approach for Semi-Infinite programs (SIPs) based on the dualization of the inner problem\, i.e.\, the problem of finding the constraint that is the most violated by a given point. After a brief introduction to SIPs and the classical solution techniques for these optimization programs\, we will consider two practical problems that can be modeled as SIPs: the aircraft conflict resolution and the collapsed k-core problem. Then\, we will present the results of the paper “Convergent algorithms for a class of convex semi-infinite programs” by M. Cerulli\, A. Oustry\, C. D’Ambrosio\, L. Liberti\, accepted for publication on SIAM Journal on Optimization. In this paper\, we focus on convex SIPs with an infinite number of quadratically parametrized constraints\, not necessarily convex w.r.t. the parameter. A new convergent approach to solve these SIPs is proposed\, leveraging the dualization technique. Based on the Lagrangian dual of the inner problem\, a convex and tractable restriction of the considered SIP is derived. We state sufficient conditions for the optimality of this restriction. If these conditions are not met\, the restriction is enlarged through an Inner-Outer Approximation Algorithm\, and its value converges to the value of the original semi-infinite problem. This new algorithmic approach is compared with the classical Cutting Plane algorithm. We propose a new rate of convergence of the Cutting Plane algorithm\, directly related to the iteration index\, derived when the objective function is strongly convex\, and under a strict feasibility assumption. We successfully test the two methods on two applications: the constrained quadratic regression and a zero-sum game with cubic payoff.  \nPlease join us at 16:00 c.t. in HS 9.
URL:https://alop.uni-trier.de/event/alop-colloquium-with-martina-cerulli/
LOCATION:Trier University E Building\, Universitätsring 15\, Trier\, 54296\, Germany
CATEGORIES:Colloquium
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20221004T074500
DTEND;TZID=Europe/Berlin:20221007T160000
DTSTAMP:20221130T083202Z
CREATED:20220303T080325Z
LAST-MODIFIED:20221130T083202Z
UID:6333-1664869500-1665158400@alop.uni-trier.de
SUMMARY:Autumn School on Model Reduction and Model Predictive Control with Differential Equations
DESCRIPTION:The Research Training Group on Algorithmic Optimization proudly announces its seventh annual \nAutumn School from October 4 – 7\, 2022. \nThis year’s focus will be on Model Reduction and Model Predictive Control with Differential Equations\n \nOptimal control problems have numerous applications in engineering and industry. One strategy for approaching them is model predictive control\, which is based on solving a series of online problems over small time periods. A major advantage of this approach is that constraints can be easily incorporated. However\, the computational complexity can become very high for certain real-time problems\, for example\, when the underlying dynamical system is a discretized partial differential equation. In such cases\, model order reduction becomes necessary to reduce the computational costs. The idea is to construct a low-dimensional surrogate model -typically in an offline phase- to replace the overly computationally expensive system underlying the optimization problem in the online phase. \n  \nThe ALOP Autumn School will feature introductory lectures on model order reduction\, model predictive control\, and related topics\, especially from the systems and control perspective \nConfirmed speakers: \nTobias Breiten (TU Berlin) \nTobias Damm (TU Kaiserslautern) \nJan Heiland (OVGU Magdeburg\, Max Planck Institute for Dynamics of Complex Technical Systems) \nBenjamin Unger (University Stuttgart\, Independent Junior Research Group Leader for Dynamic Systems) \nOrganizers:  \n \nNicole Marheineke (Trier University)  \nBjörn Liljegren-Sailer (Trier University) \nSchedule\, Location and Travel Information:  \n \nThe workshop is scheduled to begin on Tuesday\, October 4\, 2022\, with registration starting at 7:45 am\, and ending on Friday\, October 7\, 2022\, in the afternoon. \nThe workshop schedule can be found here. \nThe workshop will take place in Building E located on Campus I at Trier University. \nFor travel tips on how to get to Trier\, please check  here;\nInstructions on how to find Campus I are located here. \n \nDue to Covid restrictions\,  participation in the workshop may be limited \nThere may be other restrictions due to the pandemic.  Please be sure to follow up on this page for new developments. \nHotel Room Reservations \nWe have reserved a hotel room contingent at the Hotel Römischer Kaiser\, Am Porta Nigra Platz\, 54292 Trier. The cost for a single room is 79 € per night and includes breakfast. Please contact them directly to make your reservations referencing the AUTUMN SCHOOL 2022. \nThe contingent will be available for reservation until August 15\, 2022\, or until all available rooms have been booked. \nRegistration information: \nThe registration fee of 70 € includes a welcome reception\, the conference dinner\, refreshments\, and extra-curricular activities. Detailed payment information will be communicated upon registration.  \nTravel Stipend: \nQualified participants may be eligible for a stipend to assist with travel expenses. In order to be considered for the stipend\, please submit a CV (which should include the names and contact information of two professional references) along with a one-page letter of motivation.  You should also be prepared to submit a poster for the Poster Session. \nThe application for stipends has closed. \nRegistration is closed.
URL:https://alop.uni-trier.de/event/autumn-school-on-model-reduction-and-model-predictive-control-with-differential-equations/
LOCATION:Trier University E Building\, Universitätsring 15\, Trier\, 54296\, Germany
CATEGORIES:Autumn School
ATTACH;FMTTYPE=image/jpeg:https://alop.uni-trier.de/wp-content/uploads/2022/10/Gruppenfoto-bearbeitet.jpg
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20220804T160000
DTEND;TZID=Europe/Berlin:20220804T170000
DTSTAMP:20220721T081156Z
CREATED:20220718T130428Z
LAST-MODIFIED:20220721T081156Z
UID:6654-1659628800-1659632400@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Kendra Reiter
DESCRIPTION:On Thursday\, August 4 2022 at 16:00 c.t. Kendra Reiter\, MTU Maintenance (Hannover)\, will speak at the ALOP Colloquium about her recent work: \n  \nBuilding a geo-referenced microsimulation model with discrete optimization* \n*joint work with Dr. Ulf Friedrich\, OVGU Magdeburg and Prof. Dr. Ralf Münnich\, Trier University \nAbstract: \nMicrosimulation is an important tool to support evidence-based policies. To produce a fully geo-coded dataset\, where information is generally available on aggregate levels of different hierarchies\, micro units (households and persons) have to be placed into geo-coded dwellings. The microsimulation model involves mathematical optimization problems with integrality constraints on some of the optimization variables. It is therefore necessary to employ combinatorial optimization techniques to handle these discrete structures efficiently. More specifically\, fast algorithms for the sub-problem of address selection are needed: Given a population generated in the first step of the microsimulation process and a target region\, the households in the population have to be assigned to actual addresses within the region\, i.e.\, an address has to be selected for each household in the population. \nWhile the computation time is often not crucial when considering only a subset of the population\, e.g.\, for the simulation of a certain region or city\, the big-data setting of a complete model typically requires specialized\, fast algorithms and techniques from data science. For example\, in the address selection model for Germany more than 40 million households are assigned to over 25 million addresses while using several statistical variables to measure the quality of the assignment. General purpose heuristics such as simulated annealing do generally not solve this instance within an acceptable time limit and do not provide quality certificates. In addition\, large data sets from several sources (e.g.\, Open Street Map\, city registers\, grid-based census data) have to be combined and pre-processed in an efficient and secure way. \nPlease join us at 16:00 c.t. in HS 9.
URL:https://alop.uni-trier.de/event/alop-colloquium-with-ulf-friedrich-and-kendra-reiter/
LOCATION:Trier University E Building\, Universitätsring 15\, Trier\, 54296\, Germany
CATEGORIES:Colloquium
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20220720T080000
DTEND;TZID=Europe/Berlin:20220722T150000
DTSTAMP:20220721T101135Z
CREATED:20220215T104112Z
LAST-MODIFIED:20220721T101135Z
UID:6294-1658304000-1658502000@alop.uni-trier.de
SUMMARY:ALOP Workshop on Algorithmic Optimization and Data Science
DESCRIPTION:The Research Training Group on Algorithmic Optimization is hosting a workshop on \nAlgorithmic Optimization and Data Science\,  July 20 – July 22\, 2022. \n  \nConfirmed Invited Speakers\nProf. Dr. Gitta Kutyniok (Ludwig-Maximilians-Universität München) \nProf. Dr. Sebastian Pokutta (Zuse Institute Berlin) \nProf. Dr. Suvrit Sra (MIT Institute for Data\, Systems\, and Society) \nProf. Dr. Enrique Zuazua (Friedrich-Alexander-Universität Erlangen-Nürnberg) \nScope\n\nOptimization algorithms are a key part of almost every solution approach in data science. On the other hand\, data science or machine learning concepts can be utilized as components of optimization methods to improve state-of-the-art optimization technologies.  These viewpoints will be addressed in lively discussions during the workshop\, which will bring together experts in the fields of data science\, machine learning\, algorithmic optimization\, and everything related to these fields. \nThe topics of the workshop will include but are not limited to \n\n optimization strategies for machine learning\,\n machine learning strategies for optimization\,\n data science models based on optimization and optimal control\,\n the interplay of reinforcement learning and optimal control\,\n as well as implementations and applications.\n\nWorkshop Program\nThe workshop will begin on Wednesday\, July 20\, 2022\, at 8:00 am with registration followed by an official welcome at 9:00 am.  The workshop is scheduled to close on Friday\, July 22\, 2022\, at 3:00 pm. A detailed program may be downloaded here. \nHotel Room Reservations\nWe have a reserved a hotel room contingent at the Friedrich Hotels Trier\, Am Porta Nigra Platz\, 54292 Trier. Please contact them directly via Email: Rezeption@friedrich-hotels.de or phone +49 (651) 9770 10 0 to make your reservations referencing ALOP and Data Science. \nThe contingent will be available for reservation until July 1\, 2022\, or until all available rooms have been booked. \nConference Fee\nA conference of 50 €  is due for in-presence participants and includes refreshments\, the conference dinner complete with a wine tasting\, and a city tour of Trier. \nA conference fee of 10 € is due for remote participation via Zoom. \nSome Covid restrictions have been lifted at this time and participation in presence is unlimited.  Be sure to sign up for participation in person and use the opportunity by presenting a talk.\nRemote participation via Zoom is possible for all participants who do not plan on making a presentation\nPlease follow this page for updates in regards to restrictions due to the pandemic.  \nLocal Organizers\nRalph Bergmann\nNicole Marheineke\nRalf Münnich\nAchim Rettinger\nMartin Schmidt\nVolker Schulz \n________________________________________________________________________________________________________________________\nRegistration is now closed. \nAcceptance of your talk/presentation will be sent no later than June 30\, 2022. \n 
URL:https://alop.uni-trier.de/event/alop-workshop-on-algorithmic-optimization-and-data-science/
LOCATION:Trier University E Building\, Universitätsring 15\, Trier\, 54296\, Germany
CATEGORIES:Workshop
ATTACH;FMTTYPE=image/jpeg:https://alop.uni-trier.de/wp-content/uploads/2022/02/WS-AlgOpt-Data-Sci-scaled.jpg
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
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BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20220613T160000
DTEND;TZID=Europe/Berlin:20220613T170000
DTSTAMP:20220608T143440Z
CREATED:20220608T101314Z
LAST-MODIFIED:20220608T143440Z
UID:6548-1655136000-1655139600@alop.uni-trier.de
SUMMARY:ALOP Colloquium with Paul Swoboda
DESCRIPTION:On Monday\, June 13\, 2022\, at 16.00 c.t. Dr. Paul Swoboda\, Max-Planck-Institut für Informatik\, Saarland Informatics Campus will present his recent work titled \nSolving 0-1 ILPs with Binary Decision Diagrams \nAbstract: \nWe present a Lagrange decomposition method for solving 0–1 integer linear programs occurring in structured prediction. We propose a sequential and a massively min-marginal averaging schemes for solving the Lagrangean dual and a perturbation technique for decoding primal solutions. For representing subproblems we use binary decision diagrams (BDDs)\, which support efficient computation of subproblem solutions and update steps. We present experimental results on combinatorial problems from MAP inference for Markov Random Fields\, quadratic assignment and cell tracking for developmental biology. Our highly parallel GPU implementation improves comes close to or outperform some state-of-the-art specialized heuristics while being problem agnostic. We additionally showcase improvement that can be obtained by integrating machine learning into our solver. \n  \nThe presentation will take place in HS 9.  Please join us for coffee in E 10 at 15:45.
URL:https://alop.uni-trier.de/event/alop-colloquium-with-paul-swoboda/
LOCATION:Trier University E Building\, Universitätsring 15\, Trier\, 54296\, Germany
CATEGORIES:Colloquium
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
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BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20220411T160000
DTEND;TZID=Europe/Berlin:20220411T170000
DTSTAMP:20220301T152303Z
CREATED:20220228T102256Z
LAST-MODIFIED:20220301T152303Z
UID:6344-1649692800-1649696400@alop.uni-trier.de
SUMMARY:ALOP-Colloquium with Dr. Akhil Vohra\, University of Cambridge
DESCRIPTION:On Monday\, April 11\, 2022\, at 16:00 c.t.\, Dr. Akhil Vohra\, University of Cambridge will speak on the topic of Bayesian Persuasion: Reduced Form Approach. \nAbstract: \nWe illustrate the usefulness of reduced form representations of Bayesian persuasion problems with two applications. In one\, the reduced form representation yields a simple algorithm to determine the support of the optimal solution. In the second\, the reduced form leads to a simple greedy algorithm to determine the maximum value a sender can achieve in any cheap talk equilibrium. \nThis presentation will take place in HS 9.  Please join us for coffee and an informal meeting with the lecturer prior to the presentation in E 10 at 15:45.
URL:https://alop.uni-trier.de/event/alop-colloquium-with-dr-akhil-vohra-university-of-cambridge/
LOCATION:Trier University\, E Building\, Universitätsring 15\, Trier\, Germany
CATEGORIES:Colloquium
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
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BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20220207T160000
DTEND;TZID=Europe/Berlin:20220207T170000
DTSTAMP:20220110T113307Z
CREATED:20211102T120107Z
LAST-MODIFIED:20220110T113307Z
UID:6260-1644249600-1644253200@alop.uni-trier.de
SUMMARY:ALOP-Colloquium with Prof. Geunyeong Byeon\, Arizona State University
DESCRIPTION:On Monday\, February 7\, 2022\, at 16:00 c.t.\, Prof. Geunyeong Byeon\, Arizona State University will speak about her recent work. \nDecomposition Methods for Bilevel Problems with Convex Follower \nAbstract: Bilevel optimization formulates hierarchical decision-making processes that arise in many real-world applications such as in pricing\, network design\, and infrastructure defense planning. This work considers a class of bilevel optimization problems where the upper level problem features some integer variables while the lower level problem enjoys strong duality. We propose a dedicated Benders decomposition method for solving this class of bilevel problems\, which decomposes the Benders subproblem into two more tractable\, sequentially solvable problems that can be interpreted as the upper and the lower level problems. We show that the Benders subproblem decomposition carries over to an interesting extension of bilevel problems\, which connects the upper level solution with the lower level dual solution\, and discuss some special cases of bilevel problems that allow sequence-independent subproblem decomposition. Several novel schemes for generating numerically stable cuts\, finding a good incumbent solution\, and accelerating the search tree are discussed. A computational study demonstrates the computational benefits of the proposed method over a state-of-the-art bilevel-tailored branch-and-cut method\, a commercial solver\, and the standard Benders method on standard test cases and the motivating applications in sequential energy markets. \nThis presentation will take place via ZOOM. A link will be e-mailed prior to the event
URL:https://alop.uni-trier.de/event/alop-colloquium-with-prof-geunyeong-byeon-arizona-state-university/
CATEGORIES:Colloquium
ORGANIZER;CN="RTG ALOP at Trier University":MAILTO:ALOP@uni-trier.de
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